[PATCH v2] arm64: use SOFTIRQ_ON_OWN_STACK for enabling softirq stack

From: Ryo Takakura

Date: Wed Nov 05 2025 - 02:43:38 EST


For those architectures with HAVE_SOFTIRQ_ON_OWN_STACK use
their dedicated softirq stack when !PREEMPT_RT. This condition
is ensured by SOFTIRQ_ON_OWN_STACK.

Let arm64 use SOFTIRQ_ON_OWN_STACK as well to select its
usage of the stack.

Signed-off-by: Ryo Takakura <ryotkkr98@xxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
---

Changes since v1:
[1] https://lore.kernel.org/linux-rt-devel/20251013013508.74677-1-ryotkkr98@xxxxxxxxx/

- Add <Reviewed-by> by Sebastian.
- Add <Acked-by> by Will.

---
arch/arm64/kernel/irq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index c0065a1d7..15dedb385 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -62,7 +62,7 @@ static void __init init_irq_stacks(void)
}
}

-#ifndef CONFIG_PREEMPT_RT
+#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
static void ____do_softirq(struct pt_regs *regs)
{
__do_softirq();
--
2.34.1